Osmotic Riboflavin and transepithelial CXL Avedro.

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1 Osmotic Riboflavin and transepithelial CXL 2011 Avedro.

2 Riboflavin and the eye Riboflavin plays an important role in a number of important ocular functions including the functioning of the retinal photoreceptors and protection against nuclear cataract 1,2. Also, high levels of riboflavin were measured in the cornea relative to other ocular tissues according to a study by Batey et al. 3 1 Miyamoto et al. Proc Natl Acad Sci USA. 1998;95: Cumming et al. Ophthalmology. 2000;107: Invest Ophthalmol Vis Sci 1991; 32: Avedro 2011

3 Transepithelial, Fact or Fiction? Despite the critical role played by riboflavin in the cornea and other ocular tissues, the molecular mechanism and regulation of riboflavin translocation is poorly understood. It was generally believed that molecules traverse the corneal epithelium simply by passive diffusion through a transcellular/paracellular route. If that is the case, then epithelium removal would be essential for riboflavin to enter the stroma, as the tight junctions would make the cornea an impermeable wall for the riboflavin, hence transepithelial CXL would be Fiction!

4 Transepithelial, Fact or Fiction? However, a number of membrane transporters were identified to be involved in the translocation of various nutrients and substances across the epithelium and endothelium. Ocular transporters include carriers for peptides, amino acids, glucose, lactate, and nucleosides/nucleobases and are primarily localized on the corneal epithelium and endothelium.

5 Transepithelial, Fact or Fiction? As demonstrated by Hariharan et al.*, we believe that riboflavin transport is carrier mediated, and this correlates to the clinical results we obtained. In the light of this information, we know that transepithelial CXL is a FACT! Corneal epithelium is permeable membrane! Current Eye Research 2006; 31: Keratoconus Surgery & Cross Linking 2009; Jaypees

6 Osmotic Transepithelial CXL Preliminary Laboratory Results

7 What is microcarriers CXL? This is transepithelial CXL facilitated by a management of microcarriers. Microcarriers are used as a penetration enhancers by changing the ionic resistance of the cornea. Therefore they can be used in very low concentration to enhance the transepithelial riboflavin transport for CXL.

8 ParaCel : Osmotic Riboflavin ParaCel : 0,25% Riboflavin Methyl Cellulose Hypotonic NaCl Benzalklonium Chloride Other

9 Current Eye Research paper - October 31, 2011

10 Osmotic Transepithelial CXL First Laboratory Report

11 Laboratory results Rabbit corneas were cross-linked in vivo without removal of the epithelium, using ParaCel solution. The corneas were then examined by light and electron microscope for evidence of collagen crosslinking; Non treated eyes were compared with treated ones.

12 Light Microscope 20X According to Kohlhaas and Spoerl et al.* CXL stiffens the anterior 200 µm of the cornea only. Control OTCXL About 40% *J Cataract Refract Surg 2006; 32:

13 Light Microscope 40X According to Kohlhaas and Spoerl et al.* CXL stiffens the anterior 200 µm of the cornea only. Control OTCXL Compact straight fibres

14 Electron Microscope 16000X (upper 200 µm) Control OTCXL 21% more fibres per unit area 49 fibres / 400 nm 2 62 fibres / 400 nm 2 14

15 Electron Microscope 16000X (upper 100 µm) Control OTCXL 52 fibres / 400 nm 2 51 fibres / 400 nm 2 15 Avedro 2011

16 TAKE HOME MESSAGE Microwave technology; Fast CXL (3 minutes); LASIK Xtra and PRK Xtra? ParaCel : transepithelial riboflavin osmotically efficient

17 Interdisciplinary Journal of Microinflammation Related Journals Clinical Microbiology Allergy & Therapy Medical Microbiology & Diagnosis Avedro 2011

18 Interdisciplinary Journal of Microinflammation Related Conferences 3rd International Conference on Clinical Microbiology & Microbial Genomics Avedro 2011

19 OMICS Group Open Access Membership OMICS publishing Group Open Access Membership enables academic and research institutions, funders and corporations to actively encourage open access in scholarly communication and the dissemination of research published by their authors. For more details and benefits, click on the link below: Avedro 2011

20 THANK YOU! Avedro 2011